How might the loss of slaves affect the confederate war effort?

Virginia had the largest population of enslaved African Americans of any state in the Confederacy, and those slaves responded to the American Civil War (1861–1865) in a variety of ways. Some volunteered to assist the Confederate war effort, while many others were forced to support the Confederacy, working on farms and in factories and households throughout Virginia. Thousands escaped to the Union army's lines, earning their freedom and forcing the United States to develop a uniform policy regarding emancipation. Others remained on their home plantations and farms but took advantage of the war to gain some measure of autonomy for their families. Slaves' wartime actions most often exhibited their strong desire for freedom, and even those who chose not to escape frequently welcomed the Union army as liberators. MORE...

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.